Porcine reproductive and respiratory syndrome is the most expensive and invasive disease for pig producers on a global scale.
Though it is not occurring on every farm, it is the biggest disease problem in the pig industry, explains James Pettigrew, a University of Illinois animal sciences researcher. E. coli has also been a problem historically and continues to be on an industry-wide basis.
"Either disease can sweep through a farm so their alleviation would substantially reduce production costs," he says. "Even though many management practices have been used in the swine industry, these practices cannot guarantee freedom from disease for pigs."
Consumer concerns about bacterial resistance to antibiotics have prompted the swine industry to seek additional methods to protect the health of pigs, including special feed additives. This interest led Pettigrew and his team to explore the potential benefits of selected plant extracts.
The researchers conducted two experiments to test the beneficial effects of adding plant extracts to pig diets to combat PRRS and E. coli. In both experiments, researchers used four diets in weanling pigs, including a control diet and three additional diets that included garlic botanical extracted from garlic, turmeric oleoresin extracted from ginger, or capsicum oleoresin from pepper.
In both experiments, half of the pigs in each dietary treatment were challenged with either E. coli or PRRS virus while the other half of the pigs were non-challenged.
"We've known for a long time that plant extracts, also called essential oils or botanicals, have certain biological actions," says Yanhong Liu, a doctoral student who led the studies. "For instance, they can act as antioxidants or as antimicrobials. We wanted to test whether we could get a benefit from feeding those products in very low doses to pigs that were challenged with these specific diseases."